This is a reland of 66129430

Fixed: Unaligned reads, unspecified evaluation order.

Original change's description:
> [regexp] Bytecode peephole optimization
>
> Bytecodes used by the regular expression interpreter often occur in
> specific sequences. The number of dispatches in the interpreter can be
> reduced if those sequences are combined into a single bytecode.
>
> This CL adds a peephole optimization pass for regexp bytecodes.
> This pass checks the generated bytecode for pre-defined sequences that
> can be merged into a single bytecode.
>
> With the currently implemented bytecode sequences a speedup of 1.12x on
> regex-dna and octane-regexp is achieved.
>
> Bug: v8:9330
> Change-Id: I827f93273a5848e5963c7e3329daeb898995d151
> Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1813743
> Commit-Queue: Patrick Thier <pthier@google.com>
> Reviewed-by: Peter Marshall <petermarshall@chromium.org>
> Reviewed-by: Jakob Gruber <jgruber@chromium.org>
> Cr-Commit-Position: refs/heads/master@{#63992}

Cq-Include-Trybots: luci.v8.try:v8_linux64_ubsan_rel_ng
Cq-Include-Trybots: luci.v8.try:v8_linux_gcc_rel
Bug: v8:9330,chromium:1008502,chromium:1008631
Change-Id: Ib9fc395b6809aa1debdb54d9fba5b7f09a235e5b
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/1828917Reviewed-by: Peter Marshall <petermarshall@chromium.org>
Reviewed-by: Jakob Gruber <jgruber@chromium.org>
Commit-Queue: Jakob Gruber <jgruber@chromium.org>
Cr-Commit-Position: refs/heads/master@{#64064}